(a) Field of the Invention
The present invention relates to technology for achieving an interactive tactile interface as a tactile sensor and a tactile actuator are integrated to not only feel like a human's skin but also actively move like a muscle.
(b) Description of the Related Art
Haptics derived from the word ‘haptic,’ which means ‘touch’ in Greek, refers to study of technology for transferring force and haptic information to control a remote robot, an object under a virtual environment, or the like to a user. The haptics includes two core technologies of kinesthetic feel and tactile perception, in which the kinesthetic feel refers to technology related to transfer of large-scale force like muscular power, and the tactile perception refers to technology related to transfer of tactual perception of fine touch or pressure variation felt on a skin.
Most early study of a haptic interface has been focused on force-feedback technology related to the transfer of the kinesthetic feel, which reaches a level so high that many devices based on the haptic interface has hitherto been commercialized.
Particularly, tactile sensing and tactile display technologies are collectively called a tactile interface technology. The tactile sensing technology has relatively rapidly reached a stage of commercialization, and recently extended applications to an applied to a small mobile device represented by Apple's iPhone, Samsung Electronics' Haptic phone, etc. On the other hand, the tactile display is still in an early stage and applied to limited use such as a mouse, a dynamic Braille display for visual impaired people, etc.
The reason why the study of the tactile interface technology is important is because the tactile interface technology can be used as one fact that makes a remote environment or virtual reality be realistic together with other senses since a person's process of receiving information is determined by not only one sense but multi-modal interaction, and the tactile interface technology can make the tactile sensation of itself be plentiful in addition to the existing sensation expression. Accordingly, there is increased need of applying the tactile interface technology to a game employing the tactile sensation, a driving or flight simulator having a reaction, a medical simulator for operating or palpating a virtual patient, a patient's rehabilitation orthotic device voluntarily changeable in various physical properties, etc.
Meanwhile, the most important technical problem that should be solved to commercialize the tactile interface technology is in providing an actuating system for giving tactile stimulation. In other words, a plurality of actuators has to be integrated in a small space by miniaturizing the actuating system. However, conventional actuating systems have problems in that their structures are very hard, the whole system including the actuator, power and control circuits is generally large in comparison with the performance of the actuator, the driving speed is relatively slow, the design mechanism is complicated, and many steps are required for the fabricating process.
In particular, that the actuator is hard is the most disadvantageous to the tactile interface technology which is available only when conformable to a human's skin or various opposite objects' surfaces. The tactile interface essentially needs conformability to be embedded in the surfaces of various portable devices, robots or the like, but it is difficult to find the conformability in the technology of the actuators hitherto proposed. This is one of the most serious technical problems the tactile interface technology has.
Further, the complicated fabricating processes have the largest effect on the price of products, and thus may become another obstacle to the application of the tactile technology in the future. Thus, it is necessary for planning and designing a device by taking the price competitiveness of the fabricating process into account for commercialization in the future.
Additionally, integration between a tactile sensor vital to the tactile interface and the tactile display is an important technical problem that has to be solved in the future for developing a new interface technology. Most of the existing pin-array type tactile displays provide just a basic texture by forming a simple texture pattern, and it is difficult to find a device capable of providing active feedback based on combination of the tactile sensor and the actuator. Thus, it is important to develop a device where the tactile sensor and the actuator are combined so as to achieve a new type tactile interface that enables “Response by Touch.”